Mame basics

[keilmillerjr]

Hello! I'm relatively new to mame. I'm planning on making a Linux based mame arcade cabinet. I have used qmc2 front end with sdlmame on my iMac to test a few Roms. However, I don't fully understand how the app fully works. Other front ends seem to be rather similar.

Can some one write a beginners generic software FAQ for myself as well as others?

Some questions to get started:
What Roms are compatible with which versions of mame?
What does checking samples and image sets mean?
What does analyzing a rom set mean?
What is a chd file?
Why is there different versions of a chd file? (ie. v4/v5)

Feel free to add/rewrite questions and add answers! Remember that this should just explain the basics, and not necessarily be front end specific.

Thank you!